This application claims priority of German priority document 198 59 466.6, filed Dec. 22, 1998, the content of which is fully incorporated in the instant application.
The present invention relates to a device and method for processing substrates, in particular, semi-conductor wafers. Devices of this type are well known in the relevant technology. It is also known to supply a processing fluid to a semi-conductor wafer via a plurality of nozzles, whereby all of the nozzles are loaded in the same manner with the treatment or processing fluid.
In this regard, however, the problem exists that the consumption of the treatment fluid is relatively large, since, via all of the nozzles, the same volume of treatment is introduced. With additional, outer-lying nozzles, especially in the peripheral region of a wafer, much processing fluid is thereby consumed in an excessive manner. Moreover, the processes used in these devices are relatively slow.
In Japanese Patent JP-6-73 598A, a device for processing a semi-conductor wafer is disclosed having a first nozzle arranged essentially concentrically to the substrate and three nozzles in addition to the first nozzle, which are separately controllable. With this device, a processing fluid is conducted into a processing tank via nozzles located in the bottom of the processing tank, and fed through a lower electrode, having a grid structure, disposed in the processing tank. A substrate to be plated is retained via an upper electrode 3 above the processing tank and the processing fluid is made to overflow from the processing tank, so that the fluid comes into contact with the retained substrate. Between the lower and upper electrodes, a current is applied in order to plate the wafer. During processing, the substrate is uniformly contacted over its entire upper surface from below, and on the wafer the flow is returned in an essentially outwardly directed manner. In the outer area of the substrate, the processing fluid therefore only comes into contact with the substrate for a short time. In the edge regions of the processing tank, the processing fluid flows directly from the processing tank, without previously coming into contact with the substrate.
Therefore, the above process requires much processing fluid. The described processing is, in addition, relatively time consuming due to the outwardly directed flow on the upper surface of the wafer.
In Japanese patent JP 5-109 690 A, a device for processing substrates is described with a processing container which is divided into several zones through concentrically arranged inner walls. The respective zones are supplied with fluid via separate lines. A substrate to be treated is retained by means of a substrate carrier over the processing tank and thereby brought into contact with the treatment fluid, so that the treatment fluid is made to overflow from the processing tank.
European patent WO 97-12079 A1 shows further a device for electroplating substrates with a processing tank that, via a single line, is filled from below with processing fluid. The substrate is held above the processing tank and thereby brought into contact with the processing fluid when the processing fluid is made to overflow the tank. An electrode plate having openings which project at least partially outward is arranged within the processing tank.
The present invention therefore attempts to address the problem of reducing the medium consumption as well as the processing time in treat substrates.
In contrast to the device disclosed in the xe2x80x3598 patent, the problem is resolved with the present invention by providing a first nozzle which directs the liquid onto the substrate in a radial flow, and second nozzles which are directed transverse to the radial flow. In this regard, the radial flow is guided outwardly in a spiral shaped flow. Through the spiral shaped flow, a longer contact time of the fluid with the substrate is achieved, and therefore a smaller consumption of processing fluid. In addition, a higher dynamic of the processing fluid is provided, whereby the processing time can be reduced.
According to a preferred form of the present invention, the first nozzle is a single point nozzle in order to avoid reciprocating action between various nozzles, therefore making possible an especially uniform fluid layer on the substrate.
For a good, controlled alteration of the liquid flow through the first nozzle, the second nozzles form at least one nozzle group which runs along a prescribed shape or contour, especially a straight line. Preferably, six nozzle groups of this type are provided.
According to a particularly advantageous embodiment of the present invention, the straight lines on which the nozzle groups are constructed project tangentially relative to the first nozzle, that is, the straight lines do not run through the nozzles, rather touch the nozzles"" periphery. Through production of a tangential flow of the liquid, specifically, the radially, outwardly flowing fluid layer, which is produced through the first nozzle, the spiral shaped, outwardly directed flow, as described above, can be produced. This effect can also be achieved, for example, through a spiral shaped contour.
In this connection, the second nozzles are directed at the straight line at essentially right angles in order to direct the liquid in a substantially peripheral direction. Preferably, at least one additional nozzle is provided, which is directed back at the first nozzle. In order to produce a good tangential component, the two nozzles are directed at the substrate at an angle of less than 90xc2x0, and preferably, at an angle of 45xc2x0. Preferably, the second nozzles are point nozzles.
According to a particularly advantageous embodiment of the present invention, the first nozzle and the second nozzles are able to be loaded with different pressures, whereby via the second nozzles, an optimal production of the outward flowing fluid layer can be achieved. Via the conducted fluid volume, the incline or pitch of the spiral shaped, outwardly directed flow, for example, can be changed and thereby, the treatment process can be optimally adjusted.
According to another particularly advantageous embodiment of the present invention, the first nozzle and the second nozzles are able to be loaded with different liquids. The consumption of the processing fluid can be substantially reduced, in that only one processing fluid is conducted via the centered, first nozzle and via the second nozzles, a fluid is conducted which can be adjusted separately from the fluid from the first nozzle.
In a preferred form of the present invention, a rinsing fluid is conducted through the first nozzle for a rinsing process.
For construction of a combination processing/drying device, preferably a vacuum can be applied to the first nozzle. When a processing liquid is first applied onto the substrate via the first nozzle, this processing liquid can adhere droplet-wise on the line leading to the nozzle, or even the nozzle itself. With a subsequent drying, these droplets can leak from the line or the nozzle, which would significantly adversely affect the drying process. A leakage of this type is prevented through a vacuum applied to the first nozzle.
According to a further preferred embodiment of the invention, a gas is conducted via the second nozzles, which allows the flow of the treatment fluid to be optimally adjusted, without changing the properties of the treatment fluid. A further gas fed via the second nozzles can be used for drying the substrate after a previous treatment.
In a further embodiment, the first and second nozzles are arranged in a common base. In order to ensure a good separation of the first nozzle and second nozzles, an insert on the first nozzle is insertable into the base.
For an especially cost-effective and simple embodiment of the present invention, the second nozzles are formed in a nozzle plate of the base and are controlled via a preferably ring-shaped liquid chamber beneath the nozzle plate.
Advantageously, the base has a surface that surrounds the nozzle plate and is lower than the nozzle plate, and which has bores for receiving spacers therein. The spacers serve for adjustment of the spacing of a substrate carrier disposed over the device. Advantageously, the spacers are adjustable.
Accordingly to another preferred embodiment of the present invention, an overflow collar is provided on the base, which makes possible a fluid flow along an outer side of a substrate held in the substrate carrier, especially for drying. In order to provide this fluid flow, at least one inwardly directed nozzle is provided in or on the overflow collar. With one particularly advantageous form of the invention, the nozzle or nozzles in the overflow collar project upwardly, in order to provide the flow through the first and second nozzles. Advantageously, a plurality of nozzles are provided, which are separated by the periphery of the overflow collar, in order to provide a uniform fluid flow on the outer periphery of a substrate carrier.
With a further preferred embodiment of the present invention, at least one outlet is provided in the overflow collar to drain off the treatment fluid from the overflow collar before a drying process of the substrate and/or substrate carrier. Preferably, a tank, which is surrounded by the base, is provided to catch the treatment fluid.
Preferably, the device has a substrate carrier and a unit for conducting a fluid, especially a rinsing fluid in contact with an outer side of a substrate carrier for cleaning purposes.
The above-mentioned problem is also resolved through the method of the present invention for processing substrates, especially semi-conductor wafers, in which a fluid is applied at a right angle onto a surface of a substrate to be treated, via at least one first nozzle arranged substantially concentric to the substrate, so that the fluid applied on the substrate turns around in a radial flow, and a fluid via a plurality of separately controlled second nozzles, transverse to the radial flow, is applied to the surface of the substrate to be treated. This process has the same advantages as the above-described inventive device, in particular, an acceleration of the treatment process and a reduction of consumption of the processing fluid.
Preferred forms of the method are provided in the dependent method claims, in which the same advantages as set forth above are defined.